How do I use texture maps in Cycles nodes?
There are some things you missed :).

Maps to use:


Diffuse. Plug into Base Color input.
Roughness. Plug into Roughness input.
Normal. Use with Normal Map node and plug into Normal input. Select UV map to use.
Displacement. Use with Displacement node and plug into Displacement input.  


You need to enable material displacement through Options > Displacement > Displacement and Bump (works only in Cycles)
Only works if your geometry is subdivided.  






Bump. Don't use here, since you have a Normal map (which works better)
Specular. Don't use here. (It's more complicated, but I won't address that here)
Ambient Occlusion (AO). Don't use with Cycles, use with Eevee.